With the advent of time shared computers being accessed by a number of computer terminals at different remote locations, a need exists to prevent unauthorized entries into the host computer system from remote computer terminals.
Prior to the application of the present invention, the inventors caused a patentability search to be performed. The following are the results of that search:
______________________________________ Inventor U.S. Pat. No. Issue Date ______________________________________ F. P. Wilcox et al 3,314,051 April 11, 1967 Caudill et al 3,984,637 October 5, 1976 Matyas et al 4,218,738 August 19, 1980 James et al 3,647,973 March 7, 1972 Tulio Vasquez 4,087,635 May 2, 1978 Hashimoto 4,246,442 January 20, 1981 ______________________________________
The 1967 patent issued to Wilcox, et al (U.S. Pat. No. 3,314,051) relates to a selective call data system wherein each remote station automatically transmits its identification coding to the central station. The identification coding is then re-transmitted by the central station back to the remote station.
The 1972 patent issued to James, et al (U.S. Pat. No. 3,647,973) relates to a computer system utilizing a telephone as an input device. This patent teaches the use of a conventional telephone as an input device to a computer.
The 1976 Caudill, et al patent (U.S. Pat. No. 3,984,637) relates to a computer terminal security system wherein a local code unit located at the remote computer terminal selectively communicates with a code receiver located at the main computer. The user of the remote terminal must key in on a keyboard a preset code. The first preset code connects the terminal to the modem at the remote location. Then a second preset code is transmitted to the code receiver at the central computer. If this code is authorized, the computer is then connected to the remote terminal.
When the proper first preset code is keyed into the keyboard, the modem at the remote terminal is activated. At this point, the modem is interconnected with a code transmitter. The code transmitter transmits the second preset code over the phone lines to the code receiver at the central computer which is then compared with a code set in the code receiver. A start switch must be manually activated to transmit the second code to the code receiver. When the second code is matched, the code receiver connects the computer to the remote terminal. Hence, Caudill requires a three step process. First, the central computer is dialed up by means of a secret number which the user at the remote location carries mentally. Secondly, the user at the remote location manually keys in a first preset code from memory to gain access to the equipment at the remote location. Once access is gained, the user activates the code transmitter which transmits a second preset code to a code receiver at the computer location for verification. If the code is verified, the computer is interconnected to the phone lines.
The 1978 patent issued to Vasquez (U.S. Pat. No. 4,087,635) relates to a method and system for carrying out calculations by means of a telephone set.
The 1980 patent issued to Matyas, et al (U.S. Pat. No. 4,218,738) relates to a method for authenticating the identity of a user in an information system. The patent sets forth an authentication process using a cryptographic arrangement to the function of a user's identity number, a user's separately entered password, and a scored test pattern.
The 1981 patent issued to Hashimoto (U.S. Pat. No. 4,246,442) relates to a method and device for confirming correct connection between data terminals in data communication systems using a telephone network. Hashimoto sets forth a technique for use between facsimile units which transmit data over phone lines. When one unit establishes a telephone communication with another unit, the called unit transmits an acknowledgement signal back to the calling unit. The calling unit then transmits two separate identification codes to the called unit. One code is the identification of the calling unit and the other is the identity of the called unit. Comparison of codes is made at the called unit.
In addition to the patents uncovered in the patentability search, the article entitled Automatic Telephone Dialers, appearing in the November, 1979 issue of Radio Electronics on pages 48 through 51 sets forth a number of conventional telphone dialers that may be utilized in conjunction with remote computer terminals.
None of the prior art approaches set forth a technique wherein both identity codes for users and secret telephone numbers for host computer locations are secured in places other than in the memory of the user. Indeed, all of the above prior art systems which relate to security rely upon the memory of the user to preserve at least the secrecy of the telephone number of the host computer.